Suggestion: alternatives for initial block download

[pxsocs]

Initial block download is still a bottleneck for any Bitcoin project requiring a full synch.

Although this is a somewhat controversial topic (particularly a torrent for a recent synched blockchain), there is a tradeoff. Users could be up and running faster if the process is optimized.

A suggestion is to include on the Dojo script something similar to what the RaspiBlitz project has done, giving users other alternatives:

The script to perform this action is available here

[kenshin-samourai]

not a huge fan of this model but it may make sense in the context of dojo running on arm.

this issue depends on #16